I think it all depends on how much food you want to eat. DH and I always eat every dinner at a signature, always have. We've went twice on the deluxe dining plan (actually, it was the platinum plan but for food, it's basically the same). It's just too much food for us. Neither of us can eat an appetizer, entree and dessert for one meal a day, let alone trying to do it for two meals a day. Both trips, we left with so many credits left over and were stuffed miserably even with what we did eat. With so many trips now under our belt, we know that we are going to eat a light counter meal or a snack sometime during the day and then go to a signature for dinner, but we'll only have an entree as that's all we can eat. We used to get our desserts to go but then realized that we never ate them later so now we just skip it. If it's something special, we will split an appetizer on occasion.
If you can eat all of that food and don't mind the amount of time spent each day eating (we don't mind the time) then the plan is an excellent way to go. If you can't eat that much, you are much better off OOP.